-LRB- CNN -RRB- -- At least two confirmed tornadoes descended upon towns in western Massachusetts on Wednesday , leaving at least four dead and smashing homes and buildings across a 40-mile stretch , state officials and witnesses reported .

One person was killed in Springfield , two in nearby Westfield and one in Brimfield , about 20 miles east , Massachusetts Gov. Deval Patrick told reporters Wednesday night .

The storms struck shortly after 4 p.m. in Springfield , about 90 miles west of Boston . Dylan McDonald told CNN he watched the tornado knock down trees and scatter debris across town as he was driving with a co-worker .

`` As the light turned green , a tree fell and everything took off , '' McDonald said . `` We saw a roof fly off an apartment building . The car was tilting , but did n't turn over . ''

As many as 19 communities reported tornado damage Wednesday evening , Patrick said . The governor declared a state of emergency as the storm system that spawned those twisters moved east , with watches posted all the way to the Atlantic coast until late Wednesday .

`` It 's been particularly devastating in downtown Springfield , '' Patrick said . And he said a local official told him , `` You have to see Monson to believe it . ''

Monson resident Dolly Opper said state police were setting up roadblocks around the town , and a neighbor described the town 's center as `` war zone . ''

`` I have n't been home , '' she said . `` The steeple 's off the church across the street . It 's lying right in the front yard . ''

At J.T. 's Sports Pub , on Springfield 's Main Street , owner Keith Makarowski said he and the 10 or so patrons intially went outside to watch the darkening skies -- then retreated as the storm blew into downtown .

`` There was a ton of debris flying around , lots of roof shingles and random siding , '' Makarowski said . Several century-old buildings were damaged -- `` roofs torn off , facades ravaged , trees uprooted '' -- and a woman across the street was blown up against a building after being caught outside .

`` Luckily , two people from inside the building were able to pull her in , and she seemed like she was OK , '' Makarowski said .

Massachusetts State Police Sgt. Michael Popovics said Springfield , Monson , Westfield and seven other towns -- Agawam , Charlton , Oxford , Palmer , Sturbridge , West Springfield and Wilbraham -- reported severe damage . Sandra Ahearn , a spokeswoman for the Western Massachusetts Electric Co. , said 12,000 customers were without power in the utility 's service area and that hard-hit areas might not have electricity until the end of the week .

Patrick said he has mobilized 1,000 National Guard troops to assist with cleanup and search-and-rescue operations . The Massachusetts State Police said it had activated dog teams to look for people in damaged buildings and described many streets in Springfield as `` impassable '' due to fallen power lines and trees .

The damage came amid a wave of heavy thunderstorms that moved through the Northeast on Wednesday afternoon . Tornado watches were also issued for northern Connecticut , Rhode Island , New Hampshire and Maine until 11 p.m. Wednesday .

Though not as tornado-prone as much of the Midwest or South , Massachusetts has averaged two to three twisters per year since 1950 , according to figures from the National Oceanic and Atmospheric Administration . In 1953 , a massive tornado that struck Worcester and nearby towns killed 90 people , according to NOAA ; the last tornado to hit the state was in 2008 .

CNN 's Jennifer Westhoven , Anna Gonzalez , Matt Smith , Leigh Remizowski , Julia Talanova and Sean Morris contributed to this report .

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NEW : `` There was a ton of debris flying around , '' a witness says

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Deaths have been reported in Springfield , Westfield and Brimfield , Massachusetts

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`` Particularly devastating '' tornado damage reported in Springfield

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Gov. Deval Patrick has mobilized National Guard troops to aid cleanup